Well-bore gas burner



Nov. 5, 1963 V r J. O'BRIEN 3, 82

WELL-BORE GAS BURNER Filed Mrch 1961 2 Sheets-Sheet 1 FUEL 6A5 AIR -4-TURBINE 7 WHEEL IN VEN TOR.

LEO J. O'BRIEN BY FIGJ M a; 6

ENE)

United States atent 3,109,482 WELL-BORE GAS BURNER Leo J. GIirien,Crystal Lake, 111., assignor to The Pure Oil Company, Chicago, 111., acorporation of Ohio Filed Mar. 2, 1961, Ser. No. 92,980 2 Claims. (Cl.153-115) This invention relates to means for igniting gas-fuelfiredburners intended for use in inaccessible locations. In a more specificaspect, the invention relates to automatic means for igniting down-holeburners used in association with oil wells.

Down-hole oil-well burners are employed for a variety of purposes, suchas the control of heavy paraflinic deposits in the formation zonesurrounding the well-bore, and to apply intense heat to the formationprior to the institution of in-situ combustion. Conventional types ofburners are also frequently employed at inconveniently accessible placesfor various purposes, such as disposing by combustion of noxiouscombustible vapors or fumes.

Various means have been devised for igniting such burners, andespecially ingenious methods have been worked out for the ignition ofdown-hole oil-well burners. These burners are connected to one or moretubes through which fuel gas and air are delivered from the earthssurface, through the well-bore, to the burner. Methods for igniting suchburners include the use of pyrotechnic devices which are dropped throughthe Well-bore, as well as electric ignition techniques and devicescontrolled and operated by means of one or more electric cables whichextends downward through the Well-bore from the surface of the earth.While such methods and means are often satisfactory for initiallyigniting the burner, they are often cumbersome, expensive, andinconvenient, especially when it becomes necessary to reignite theburner at intervals, because the flame is extinguished intentionally orinadvertently.

It is an object of this invention to provide means for the automaticignition of gas-fuelfired burners. Another object of this invention isto provide automatic means for reigniting the burner in instances wherethe flame is accidentally extinguished. Still another object of thisinvention is to provide means for the automatic deactivation of theignitor shortly after ignition has occured. Still another object of thisinvention is to provide an automatic ignitor for a burner located in aninaccessible position, which ignitor requires no connecting electriccable for actuation. Another object of this invention is to provide adownhole ignitor for automatically igniting a gaseous fuel stream, whichignitor operates automatically upon the institution of fuel flow, toignite the fuel.

Briefly, the apparatus of this invention comprises an electricallyoperated spark or resistance-wire ignitor in association with agaseous-fuel burner, and a turbinegenerator assembly disposed inassociation with the fuel inlet-line to the burner, so that the gaseousfuel flowing to the burner drives the turbine and generates the electricpotential which operates the electric ignitor.

This invention is best described with reference to the drawings, ofwhich,

FIGURE 1 is a sectional View of a well bore in which is disposed adown-hole burner incorporating the novel ignitor means of thisinvention;

FIGURES 2, 3, and 4 are schematic lay-outs of alternate ignitor means inaccordance with this invention.

Referring to FIGURE 1, a gaseous fuel, such as methane, introducedthrough tubing 10, and air, introduced through tubing 12, are combinedabove the surface of the earth and flow through vertical well tubing 14,through burner inlet 15, and to the nozzle 16 of the ice burner. Themixture of gas and air is burned in the combustion zone 18 of well-bore20, zone 18 being isolated and confined by means of we'll-bore packer22. The hot combustion products flow through perforations 24 in wellcasing 26 and then into the surrounding formation.

In accordance with this invention, turbine wheel 27 is connected bymeans of shaft 28 to generator 29. The generator 29 is located Withinhousing 30 which forms a part of the burner assembly, and is located atthe fuelgas inlet to the burner. Within the fuel-gas inlet 15 isdisposed turbine wheel 27, such that the flow of fuelgas, or fuel-gasand air mixtures, to the burner causes rotation of the turbine wheel 27.The turbine utilizes the energy of the flowing mixture of fuel and airto drive generator 29 and generate electric energy, which energy isstored in condenser 31. Wire 32, which is insulated to withstandcombustion temperature, is positioned in tube 34, which latter tube isconnected to the generator housing. Surrounding tube 34 is positionedtubing 36, which is an extension of the housing 34} within which thegenerator and condenser are supported, by radial struts which are notshown in the drawing.

Jack-and-plug assembly 48 and bimetallic element 42 are located inseries, and control the current flow in wire 32 so that when either ofthese elements provide an open circuit, no current can flow toelectrodes 44 to produce the igniting spark. The circuit is completeonly when the bimetallic element is cool, and when perforated housing 46engages the bottom of the well and the pipe string above is dropped afew inches with respect to housing 46 to close the connection betweenjack 50, which is supported by housing 46, and plug 52, which issupported by tube 34.

The fuel and air mixture is ignited in combustion zone 18, the circuitto the electrode being broken automatically when the temperature risessufficiently to actuate bimetallic strip 42. The production of a sparkmay be prevented, when so desired, by lifting the tubing string off thewell bottom, thereby disengaging jack-and-plug assembly 48. It isevident that an igniting spark will otherwise occur each time thecondenser becomes sufficiently charged to produce an arc dischargeacross the spark gap between electrodes 44.

Referring to FIGURES 2, 3, and 4, alternate electricgenerating andigniting means are shown. Referring to FIGURE 2 turbine wheel 60 drivesgenerator 62 through shaft 64. The output of the generator, which may bea conventional low-voltage generator having a fractional watt output, isconducted through wire 66 to bimetallic element 68. When bimetallicelement 68 is cold, connection is made to wire 70 which contacts thebimetallic element at 72, and is connected to the input of electric coil74. High-tension wire 76 leads from coil 74 to spark gap 78. The outputof generator 62 may be a high-frequency AC. voltage, and this voltagemay be increased to a suitable potential to jump spark gap 7 8 by meansof the windings of coil 74. Alternatively, the output of generator 62may be a direct current, and coil 74 may be equipped with a continuouslyoperating relay device to make and break the connection in the primarycircuit of the coil. Such spark coils are well known and were commonlyused in the ingition systems of older automobiles. lt is evident thatupon the institution of fuel flow, rotation of turbine wheel 60 willcause an electric current to be produced. This current actuates theignition coil to produce a spark at spark gap 78 to ignite a combustiblefuel-and-air mixture. After burning has commenced, bimetallic element 68becomes heated and bends to break contact and disconnect the ignitioncoil 74. In this manner, excessive deterioration of the elements formingthe spark gap may wire 92, bimetallic element 94, contact 96, and returnwire 98 to ignition resistance element 99. Generation of electricity bygenerator 90 results in the heating of resistance element 99, to productignition of the fuel-gas mixture. Bimetallic element 94 is provided toprevent over-heating and deterioration of the resistance element. Thebimetallic element 94 serves to break connection with generator 90 afterthe occurrence of ignition of the combustible mixture of fuel and air.

It will be evident that with respect to each embodiment described, theflow of fuel gas to the burner results in the generation of an electricpotential which automatically operates ignition means to start the firein the burner. It is evident that in each case, when the flow of fuelgas is terminated, as by closing a fuel-line control valve, operation ofthe generator terminates. However, upon reopening of the control valveto again provide fuel to the burner, ignition is automatically provided.In the case of the constant-ignition-providing embodiments, as shown inFIGURE 3, the ignition means operates continuously as long as fuel isflowing to the burner. Hence, if the flame becomes extinguished for anycause, reignition is automatically immediately provided. In the exampleswhere a bimetallic element is used to interrupt operation of theignition device after burning of the fuel has commenced, if the flamebecomes extinguished for any cause other than termination of the fiow offuel to the burner, reignition will automatically be provided upon thecooling of the bimetallic element to re-establish electrical connectionbetween the generator and the ignition device.

' It will be evident that the ignition means of this invention may beemployed with conventional gas burners, and is not limited to the use ofdown-hole oil-well burners. In cases where fuel only is provided to theburner, and mixed with available atmospheric air for combustion, theoperation of the device will be the same as described in the specificembodiment, except that only the gaseous fuel will be available to drivethe turbine wheel. This is not a serious limitation, since the amount ofelectricity needed to operate the ignitor is not great. Depending uponwhether spark ignition or resistance-element ignition is employed, thepower requirement for the generator may vary from a tenth of a watt to100 watts. In most instances, however, a fractional wattage generatorwill provide ample power for ignition, and can most conveniently beemployed without requiring serious modification of conventional burnerstructure. The apparatus of this invention may therefore be adapted foruse with conventional gaseous fuel burners, such as those described inUS. Patents 2,506,853 and 2,832,417. It should be understood that theignition means comprising resistance wires, spark coils, etc., have beendescribed by way of illustration only, and the invention should not beconsidered to be limited to these specific ignition means.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An apparatus for burning a combustible gaseous fuel in a well-borecomprising (1) a downhole burner unit including (a) a burner housinghaving a gaseous fuel inlet opening at the upper end thereof and adaptedto receive support from the interior of a well-bore,

(b) electrically actuated ignitor means within said burner housing, and

(c) a first electrical terminal supported adjacent the upper end of saidhousing and connected electrically to said ignitor means,

(2) a housing having open upper and lower ends, said upper end beingadapted for connection to a gaseous fuel well tubing, said lower endbeing connected with said opening in said burner housing,

(3) electricity generating means supported within said last namedhousing,

(4) a turbine wheel connected to drive said generator means andpositioned to be driven by the flow of gaseous fuel through said lastnamed housing, and,

(5) a second electrical terminal connected to the output of saidgenerating means, supported for movement with said last named housing,and positioned adjacent the lower end of said last named housing tocontact said first terminal when said last named housing is in a loweredposition with respect to said burner housing, but not to contact saidfirst terminal when said last named housing is in a raised position withrespect to said burner housing.

2. An apparatus in accordance with claim 1 in which said first andsecond terminals are disposed concentrically with respect to saidopenings at the upper end of said burner housing and at the lower end ofsaid last mentioned housing, respectively.

References Cited in the file of this patent UNITED STATES PATENTS1,635,104 Woods July 5, 1927 2,346,704 Ray Apr. 18, 1944 2,398,106McCollum Apr. 9, 1946 2,482,794 Peterson Sept. 27, 1949 2,542,666 HallFeb. 20, 1951 2,997,105 Campion et a1 Aug. 22, 1961 FOREIGN PATENTS480,620 Italy May 7, 1953

1. AN APPARATUS FOR BURNING A COMBUSTIBLE GASEOUS FUEL IN A WELL-BORECOMPRISING (1) A DOWNHOLE BURNER UNIT INCLUDING (A) A BURNER HOUSINGHAVING A GASEOUS FUEL INLET OPENING AT THE UPPER END THEREOF AND ADAPTEDTO RECEIVE SUPPORT FROM THE INTERIOR OF A WELL-BORE, (B) ELECTRICALLYACTUATED IGNITOR MEANS WITHIN SAID BURNER HOUSING, AND (C) A FIRSTELECTRICAL TERMINAL SUPPORTED ADJACENT THE UPPER END OF SAID HOUSING ANDCONNECTED ELECTRICALLY TO SAID IGNITOR MEANS, (2) A HOUSING HAVING OPENUPPER AND LOWER ENDS, SAID UPPER END BEING ADAPTED FOR CONNECTION TO AGASEOUS FUEL WELL TUBING, SAID LOWER END BEING CONNECTED WITH SAIDOPENING IN SAID BURNER HOUSING, (3) ELECTRICITY GENERATING MEANSSUPPORTED WITHIN SAID LAST NAMED HOUSING, (4) A TURBINE WHEEL CONNECTEDTO DRIVE SAID GENERATOR MEANS AND POSITIONED TO BE DRIVEN BY THE FLOW OFGASEOUS FUEL THROUGH SAID LAST NAMED HOUSING, AND, (5) A SECONDELECTRICAL TERMINAL CONNECTED TO THE OUTPUT OF SAID GENERATING MEANS,SUPPORTED FOR MOVEMENT WITH SAID LAST NAMED HOUSING, AND POSITIONEDADJACENT THE LOWER END OF SAID LAST NAMED HOUSING TO CONTACT SAID FIRSTTERMINAL WHEN SAID LAST NAMED HOUSING IS IN A LOWERED POSITION WITHRESPECT TO SAID BURNER HOUSING, BUT NOT TO CONTACT SAID FIRST TERMINALWHEN SAID LAST NAMED HOUSING IS IN A RAISED POSITION WITH RESPECT TOSAID BURNER HOUSING.